<template>
<!-- 写HTML标签 -->
<p class="p1">{{ message }}</p>
<button @click="changeMsg">修改message</button>
</template>

<script setup>
// vue3的组合式API写法
import { ref } from 'vue'
const message = ref('Hello Vue3')
const changeMsg = () => message.value = 'Hello World'
</script>

<style scoped>
.p1 {
  color: red;
}
</style>